CN1248817C - Soft brazing method - Google Patents
Soft brazing method Download PDFInfo
- Publication number
- CN1248817C CN1248817C CNB031556450A CN03155645A CN1248817C CN 1248817 C CN1248817 C CN 1248817C CN B031556450 A CNB031556450 A CN B031556450A CN 03155645 A CN03155645 A CN 03155645A CN 1248817 C CN1248817 C CN 1248817C
- Authority
- CN
- China
- Prior art keywords
- soldering
- composition
- solder
- bathed
- lead
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
- H05K3/3489—Composition of fluxes; Methods of application thereof; Other methods of activating the contact surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K1/00—Soldering, e.g. brazing, or unsoldering
- B23K1/08—Soldering by means of dipping in molten solder
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
- Molten Solder (AREA)
Abstract
In the method of soldering electronic components to wiring boards by using molten lead-free solder, the solder composition in a molten solder bath is managed so that the contents of copper element and lead element may fall within the ranges of 0.5-0.05 wt% and 300-3,500 ppm, respectively. The management of the solder composition in the solder bath is performed by fractionating the solder from the solder bath, and performing elemental analysis on the fractionated solder after the operating hour of the solder bath reaches a prescribed value or the number of wiring boards dipped in the solder bath reaches a prescribed number. When at least either the copper element or lead element deviates from a prescribed range, the components of the solder bath is adjusted, so that the composition of the solder bath may fall within a prescribed range.
Description
[technical field]
The present invention relates to use the soldering of Sn-Ag-Cu class that electronic components are soldered to method on the circuit board, particularly the control composition that soldering bathes that flows carries out the high soft soldering method of reliability.
[background technology]
As the means of on circuit board, assembling solder and electronic components are installed, what extensively carry out is that the soldering bath that the fusion soldering is housed was contacted with the following of circuit board, and the what is called that the lead-in wire of electronic components is connected with the terminal portion of circuit board flows (with reference to the open 2001-308508 communique of Japan Patent) is installed.
, in the past, as the brazing material that makes Wiring pattern and electronic components carry out combination, the plumbous cocrystallization soldering of tin was owing to advantages such as the wettability of electrode material, connection reliability, solder temperature are widely used in this installation.; in the time of can widely used this leaded brazing material goes out of use in electric machine; dissolve harmful lead in environment, owing to cause the dangerous big of heavy metal pollution, the application of lead-free so-called unleaded brazing material in recent years develops rapidly.
As flowing the lead-free of usefulness is installed at present, Sn-Ag-Cu class, Sn-Cu class, the material of Sn-Zn class etc. is known, the brazing material of Sn-Ag-Cu class, Sn-Cu class is used always as stable brazing material in these brazing materials.
Also have, as the connector portions material of electronic components, can use Cu or Fe or as the Fe-Ni class alloy of 42 alloy type, on the surface of this connector portions material, the wettability when improving solder is carried out the plating that Sn-Pb etc. forms.
; the installation if the general at present unleaded brazing material that uses of use flows; when soldering is solidified; the intermetallic compound of needle-like and precipitate; soldered joint portion and and its other approaching undesirable part between adhere to the commissure state; produce so-called electric bridge, and cause short circuit.
As the method for improving this electric bridge phenomenon, in the soft soldering apparatus of installing that flows, in the moment that the solder part breaks away from from soldering is bathed, partly stoping the formation of fibrous material, the generation that prevents electric bridge with heating solders such as heaters is known (with reference to the open 2001-308508 communique of Japan Patent)., this method need be transformed soft soldering apparatus itself, and this complicated method is bathed the moment that breaks away from circuit board from soldering and must be sprayed hot blast, requires very high accuracy control.
The object of the present invention is to provide,, effectively prevent soldering electric bridge phenomenon by simple method in order to improve the above-mentioned defective in the mobile installation method of using no lead solder, and the high welding method of connection reliability.
[summary of the invention]
The present invention is a soft soldering method, in order to solve the problem of above-mentioned prior art, soldering at the no lead solder that uses fusion Sn-Ag-Cu class is carried out in the soft soldering method of circuit board and electronic components, it is characterized in that adjusting the composition that soldering is bathed, make the copper of fusion soldering in bathing in the scope of 0.5～1.15 weight %, and plumbous for being equivalent to the concentration of impurity.
In the soft soldering method of the present invention, plumbous composition is preferably in the scope of 300～3500ppm.
Also have, in the invention described above, the adjustment of forming is bathed in soldering, can add at least a not cupric and other plumbous composition by in the composition of bathing in above-mentioned soldering, perhaps adds to bathe from initial soldering and reduces the material of copper and lead forming and carry out.
Also have, among the present invention, the control of forming is bathed in soldering, can be by after bathing the duration of runs through the soldering of regulation, from bathing, soldering extracts brazing material, the brazing material that extracts is carried out elementary analysis, at least a in copper and lead departed under the situation of prescribed limit, bathe in the material in above-mentioned soldering, add elemental composition that at least a formation soldering bathes so that soldering is bathed and formed in prescribed limit and carry out, perhaps, after the circuit board number by dipping in above-mentioned soldering is bathed reaches defined amount, from bathing, above-mentioned soldering extracts brazing material, the brazing material that extracts is carried out elementary analysis, at least a in copper and lead departed under the situation of prescribed limit, bathes in the material in above-mentioned soldering, adds elemental composition that at least a formation soldering bathes so that soldering is bathed and formed in prescribed limit and carry out.
The invention described above is based on and has studied above-mentioned discovery that the result that uses the installation that the soldering of flowing bathes obtains.Promptly, the copper that does not corrode circuit board bonding land and Wiring pattern that Sn-Ag-Cu class brazing material can carry out in the solder operation, the soldering of body lotion stable components, even in this soldering is bathed, from the conductive material that circuit board uses, dissolve copper, if when in soldering is bathed, accumulating the concentration more than the normal concentration, the viscosity that soldering is bathed rises, and judgement is the reason that produces electric bridge.Therefore, this soldering is bathed, regularly carry out composition analysis, when the amount of copper was shown as the above value of regulation, the raw material adjustment composition by adding deficiency or lacking proved and can avoid the electric bridge phenomenon effectively.
Also have, when in this soldering is bathed, existing the lead that is equivalent to impurity concentration to exist, because the viscosity that soldering is bathed reduces, both made in the soldering that contains higher concentration copper is bathed, also can suppress electric bridge produces, can prolong soldering and bathe the cycle of forming adjustment, reduce the number of using of soldering operation, finish soldering thereby can carry out effective soldering bath control.
Among the present invention the control range of forming is bathed in soldering and be set at copper 0.5～1.15 weight %, plumbous scope is equivalent to the scope of impurity, in more detail, be in the scope of 300～3500ppm, its reason is, if the content that the soldering of copper is bathed is lower than 0.5%, exists wettability to reduce, the big problem of corrosion of the copper product that uses in problem that the reliability that soldering connects reduces and the circuit board and bad.On the other hand, if copper content is higher than 1.15 weight %, the viscosity that soldering is bathed rises, or forms the intermetallic compound and the precipitate of needle-like easily, or becomes the reason of soldering electric bridge, and soldering defect rate (bad corrected rate) increases.
Also have, if the content that plumbous soldering is bathed is lower than 300ppm, the suitable compositing range of copper is narrowed about 0.5～1.0 weight %, increases soldering and bathes the operation of adjusting, and operating efficiency reduces.On the other hand, if plumbous amount is higher than 3500ppm, not only the part of solidifying middle soldering of brazing material is peeled off, and so-called break-off mostly occurs.And need adopt other countermeasure and uneconomical for fear of the environmental problem of plumbous stripping.
In the invention described above, the adjustment of forming is bathed in above-mentioned soldering, bathes in the composition in above-mentioned soldering, preferably carries out with other plumbous composition by adding at least a not cupric.And in the invention described above, the adjustment of composition is bathed in above-mentioned soldering, bathes in the composition in above-mentioned soldering, preferably bathes the material that becomes to be grouped into that reduces copper and lead the composition by interpolation from initial soldering and carries out.
In the invention described above, the composition that above-mentioned soldering is bathed is controlled to be, after the duration of runs is bathed in the soldering of process regulation, from bathing, soldering extracts brazing material, carry out elementary analysis, depart under the situation of prescribed limit at copper and plumbous match ratio, preferably soldering bath composition is carried out within the limits prescribed by adding at least a soldering bath composition.
Also have, in the invention described above, the composition control that above-mentioned soldering is bathed, with the circuit board of defined amount in soldering is bathed behind the dipping, from bathing, soldering extracts brazing material, carry out elementary analysis,, preferably soldering bath composition is carried out in prescribed limit by adding at least a soldering bath composition in copper and plumbous departing under the situation of prescribed limit.
In the invention described above, be people of the present invention in order to solve the result of above-mentioned subject study, obtained the opinion that is found to be the basis with following.That is, in unleaded soldering, along with the repetition of solder operation, during soldering bathe formed the copper of forming circuit pattern and constitute the lead-in wire of electronic component copper dissolution, be accumulated in during soldering bathes.As a result, the viscosity that soldering is bathed rises, and in the solder operation, generates the intermetallic compound and the precipitate of needle-like, and these can judge the reason that becomes electric bridge.And, equally in no lead solder, if bathe form in dissolving sneak into the lead that contains in the lead-in wire plated material etc., enlarged the solidification temperature range of connecting portion.Particularly, if lead segregation is slightly solidified in the top layer part soldering that soldering connects, soldering is inner, and not solidified to dissolve brazing area in low viscosity residual, in the process that they solidify again because the solidification shrinkage stress of substrate etc. increases, produce that soldering connects to peel off distortion be obvious.Therefore, expect and to bathe composition by adjusting the control soldering, prevent this electric bridge and peel off phenomenon, finished the present invention thus.
[specific embodiment]
Under regard to the present invention, below describe embodiment in detail.
The unleaded brazing material that uses among the present invention can use known material as Sn-Ag-Cu class brazing material.Brazing material because various material differences roughly keep dissolving, is used for the solder of flowing and installing under 250 ± 2 ℃ temperature range under blanket of nitrogen.
Along with the solder process number purpose increase of circuit board, copper that dissolving is sneaked in soldering is bathed and lead, other metal, the soldering bath is formed, and along with the duration of runs is bathed in soldering, or floods the increase of circuit board number in soldering is bathed, and composition also changes thereupon.Promptly, copper, lead and iron etc., the metallic element that the material that the Wiring pattern material of circuit board, the lead material that is assemblied in the electronic component on the circuit board or this wire surface are electroplated etc. contains dissolves in soldering is bathed sneaks into, the ratio of these metallic elements rises, and the ratio of elements such as obsolete tin, silver reduces relatively in the circuit board.
Thus, often or with proper spacing bathe the extraction brazing material from this soldering, the elemental microanalysis method of use icp analysis method etc., the component that the quantitative analysis soldering is bathed is checked the composition that soldering is bathed.Then, depart from the prescribed limit stage, bathe the element that lacks in forming, in soldering is bathed, add copper that ratio increases and the lead-free formation element plumbous the removing in order to replenish soldering at this composition.Or material is bathed in the abundant soldering of adding in soldering is bathed outside copper and the lead of composition.
The interpolation of this complementary element can be added the various metallic elements of shortage respectively, also can add in advance the formation metallic element outside copper and the lead to be dissolved the granular material of alloying.According to the method for this interpolation alloying particle, can carry out soldering apace and bathe composition adjustment, be practical.Also have, if with these metallic element add to soldering bathe in before dissolve, add as molten metal, can carry out soldering further and bathe the rapid adjustment of forming.Also have, metal can be used as the material interpolation that reduces the match ratio of copper and lead during stage use soldering bath is formed in the early stage as a supplement.If like this, though form the frequency height of adjusting, form the result who adjusts, can shorten and form the time that reaches homogeneous.
The soldering 600kg that Sn-Ag-Cu forms of having that will contain 350ppm lead dissolves and remains on 250 ℃ and bathe as soldering.This soldering contains 0.52% Cu in bathing.Flood element therein and count 3.5 seconds of the back side of two sides circuit board of 1100, carry out solder.So each 10,000 of sort circuit plates of handling are bathed the state that the material maintenance dissolves from soldering, extract about 500g brazing material, carry out elementary analysis with the ICP elemental microanalysis method, bathe the material ratio of components with the soldering at initial stage.Repeat this cycling 5 times, plumbous amount reaches 3100ppm, and the amount of copper reaches 1.15%, and the soldering of adding in being bathed by the soldering of routine is changed into the Sn-Ag class from the Sn-Ag-Cu class.
In this soldering of forming adjustment is bathed, carry out the installation of 100,000 circuit board, the electric bridge incidence is below 600ppm, and the incidence of peeling off is 2%.At this, the electric bridge incidence is the ratio of always counting of electric bridge generation number divided by solder, and peeling off incidence is to peel off the ratio of always counting of number divided by solder that take place.
On the other hand, do not carry out this soldering fully and bathe and form during the soldering of adjusting bathes, carry out the result of solder of 50,000 circuit board, soldering electric bridge incidence increases later on from the 40th, 000, reaches 1000～1200ppm.Also have, peel off incidence and reach about 50%.
According to the present invention of above explanation, owing to use the no lead solder that does not cause environmental pollution, long-time use soldering was bathed can not produce the soldering electric bridge and peel off phenomenon, brought into play being characterised in that the effect that can carry out the high solder of reliability.
Claims (3)
1. soft soldering method, using the unleaded Sn-Ag-Cu class scolder of fusion to carry out in the method for solder of circuit board and electronic components, it is characterized in that the composition of adjusting the soldering bath makes copper in the scope of 0.5～1.15 weight %, and lead is the interior concentration of scope of 300～3500ppm.
2. the soft soldering method put down in writing of claim 1, it is characterized in that the adjustment that above-mentioned soldering bath is formed, in the composition of bathing in above-mentioned soldering, adds at least a not cupric and other plumbous composition, perhaps add to bathe and reduce the material of copper and lead forming and carry out from initial soldering.
3. claim 1 or 2 soft soldering methods of being put down in writing, it is characterized in that composition for above-mentioned soldering bath, after the duration of runs is bathed in the soldering of process regulation, from bathing, soldering extracts brazing material, the brazing material that extracts is carried out elementary analysis, and at least a in copper and lead departed under the situation of prescribed limit, forms within the limits prescribed for soldering is bathed, by bathing in the material, add the elemental composition that at least a formation soldering bathes and carry out in above-mentioned soldering.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP215809/2002 | 2002-07-24 | ||
| JP2002215809A JP2004063509A (en) | 2002-07-24 | 2002-07-24 | Method for soldering |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1486813A CN1486813A (en) | 2004-04-07 |
| CN1248817C true CN1248817C (en) | 2006-04-05 |
Family
ID=31937751
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031556450A Expired - Fee Related CN1248817C (en) | 2002-07-24 | 2003-07-24 | Soft brazing method |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2004063509A (en) |
| KR (1) | KR100560708B1 (en) |
| CN (1) | CN1248817C (en) |
| TW (1) | TWI221758B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI465312B (en) * | 2005-07-19 | 2014-12-21 | Nihon Superior Co Ltd | A replenished lead-free solder and a control method for copper density and nickel density in a solder dipping bath |
-
2002
- 2002-07-24 JP JP2002215809A patent/JP2004063509A/en active Pending
-
2003
- 2003-07-23 TW TW092120104A patent/TWI221758B/en not_active IP Right Cessation
- 2003-07-23 KR KR1020030050542A patent/KR100560708B1/en not_active IP Right Cessation
- 2003-07-24 CN CNB031556450A patent/CN1248817C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| TWI221758B (en) | 2004-10-01 |
| CN1486813A (en) | 2004-04-07 |
| TW200403965A (en) | 2004-03-01 |
| KR100560708B1 (en) | 2006-03-16 |
| JP2004063509A (en) | 2004-02-26 |
| KR20040010350A (en) | 2004-01-31 |
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| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20060405 |